Natural inclination - what is it like packaging with materials from nature?
They make plastic bottles out of plants, protect delicate goods with
wool and use rubber to make more elastic plastic. So, what is it like
working with natural materials? Eoin Redahan asks the professionals.
Ormondroyd|desc=|link=none|align=left|width=99|height=100]WOOD: Dr Graham Ormondroyd (GO) Head of Materials Research, Biocomposites Centre at Bangor University, UK.
BIOPOLYMERS: Andrew Gill (AG) Technical Manager of Floreon Transforming Packaging Ltd in Hull, UK.
RUBBER: Dr Stuart Cook (SC) Director of Research, Tun Abdul Razak Research Centre in Hertford, UK.
GENERAL PACKAGING: Keith Barnes (KB) Chairman of the Packaging Society in London, UK.
BIOPOLYMERS: Angela Morris (AM) CEO of the Wool Packaging Company Limited in Shropshire, UK.
How are you using natural materials? What are the advantages of the materials you use?
GO - The nature and beauty of wood mean that it can be used
purely for its aesthetics, while the same material can also be used in
load bearing construction applications. The weight-to-strength ratio of
timbers makes wood suitable for many applications.
AG - Biopolymers are typically made by converting starch to sugar
(or starting with sugar directly), which is fermented to produce
polymer building blocks (monomers) or their precursors. Established
plastics such as PE can be made this way, as can relatively new polymers
such as PLA. Bioplastics are generally seen as a greener alternative to
SC - Natural rubber accounts for more than 40% of global rubber
use (10 million tonnes). The inherent strength of natural rubber,
arising from the regularity of its structure, makes it the material of
choice in a wide range of applications, from tyres to engineering
products and gloves.
KB - All areas of packaging involve natural materials. One
example is paper and board, where the main raw material is wood, but
other plant life, such as hemp, sisal and straw, could be used where the
land or climate is not good. Some of these organic materials have parts
that cannot be used for paper, such as sugar beet waste. In this case,
by applying clever chemistry, the starch is extracted and converted into
oil, which can be turned into plastics.
AM - We use 100% pure sheep’s wool in our insulated packaging for
temperature sensitive products. Wool is a natural smart ﬁbre that
provides a range of unique innate beneﬁts and superior insulation. Wool
has a natural crimp, and the outer part of the ﬁbre is made of scales
that trap air, making it effective in reducing heat transfer, as air
does not conduct or disperse heat well. With wool’s ability to breathe,
it absorbs and releases moisture from the air, being hygroscopic, which
in turn generates tiny amounts of heat that stabilise temperature
changes and create a natural buffering effect. This insulating factor
can work both ways, by retaining heat or keeping heat out.
How expensive are the natural materials you work with compared with
their synthetic alternatives? Is this a barrier to progress?
GO - Timber and timber products can be relatively cheap, for
example particleboard is much cheaper than an equivalent synthetic
product. However, when a piece of wood is bought for its beauty, the
price of the raw timber is often high. This high price can be compounded
by the scarcity of the timber.
AG - Biopolymers tend to be more expensive due to economies of
scale, as production is scaled up to meet demand. Green, or bioderived
PE, currently sells for around 30% more than identical oil-derived PE.
The higher price can be an obstacle for newer materials such as PLA,
although plant-derived plastics suffer less price ﬂuctuation compared to
those produced from oil.
SC - As a commodity, the price of natural rubber relative to
relevant synthetic rubbers varies over time, depending on the balance
between supply and demand. Supply has eased in the past two years, and
this has been reﬂected in the price. While for some products such as
tyres, there is some scope for adjusting the relative amounts of natural
and synthetic rubber used (and some accommodation is made on the basis
of price), there is a limit to the extent that this can be practised. In
recent years, there has been concern that the future supply of natural
rubber will not be adequate to meet demand.
AM - Wool-insulated packaging is competitive and in some
instances actually shows a saving over synthetic alternatives. The
initial outlay is sometimes slightly more expensive but when transport,
storage, quantity of ice packs required, waste management, product
damage and spoiled product costs are included in the calculation, wool
packaging can show a substantial saving.
Have you explored the use of natural material composites in your ﬁeld? What possibilities do they open up?
GO - Natural material composites have been extensively used in
the timber industry throughout history. Plywood, medium-density
ﬁbreboard, chipboard, oriented strand board and laminated veneer lumber
are all composites used in construction, furniture and other
AG - A lot of work has been done on reinforcing plastics and
biopolymers with natural ﬁbres such as ﬂax, to expand their range of
applications. Progress has been made but there are still technical and
commercial obstacles to be overcome. The variability of plant-based
ﬁbres needs to be addressed.
SC - Natural rubber composite materials are already widely used.
The rubber ﬁllers provide additional hardness and toughness, as well as
reducing the cost of the product. Blending natural rubber with other
rubbers provides characteristics that are not available from single
constituent rubbers. Blends have also been developed with plastic
materials to produce a composite that is processed like a plastic, but
which retains elastic properties.
AM - During our research, we have considered using natural
material composites. Initial trials have shown that our wool can be
combined with other natural materials to enhance the properties of wool.
This opens up endless possibilities, creating enormous commercial
potential within the packaging sector.
For more information, contact Angela Morris, Chair of IOM3’s Natural Materials Association firstname.lastname@example.org